Preparation of High-Fidelity Entangled Cat States with Composite Pulses

A protocol is proposed for the preparation of high-fidelity entangled cat states with composite pulses. The physical model contains two Kerr-nonlinear resonators and a cavity. By properly designing the parameters, each Kerr-nonlinear resonator is confined in the cat-state subspace and the entangled cat states can be generated efficiently. Composite two-photon drives are introduced with multiple amplitudes and frequencies to improve the fidelity of the entangled cat states in the presence of parameter errors. The performance of the protocol is estimated by taking into account the parametric errors and decoherence. Numerical simulation results show that, the protocol is robustness to timing error, detuning error, and decoherence. It is hoped that the protocol may provide a method for preparing stable entangled cat states.